Use of autotransformer-like antennas for downhole applications

摘要

An apparatus for estimating a property of an earth formation penetrated by a borehole, apparatus including: a carrier configured to be conveyed through the borehole; a transducer disposed at the carrier and configured to transmit and/or receive electromagnetic energy into and/or from the earth formation to estimate the property; wherein the transducer includes a plurality of inductively coupled elements in a series, each element configured to transmit and/or receive electromagnetic energy and at least a first connection to a first element in the plurality and a second connection to a second element in the plurality with at least one of the first element and the second element being disposed between end transducer elements in the series.

主权项

1. An apparatus for estimating a property of an earth formation penetrated by a borehole, apparatus comprising:
a carrier configured to be conveyed through the borehole; a transducer disposed at the carrier and configured to transmit and/or receive electromagnetic energy into and/or from the earth formation to estimate the property; wherein: the transducer comprises a plurality of inductively coupled elements in a series, each element configured to transmit and/or receive electromagnetic energy, and at least a first connection to a first element in the plurality and a second connection to a second element in the plurality with at least one of the first element and the second element being disposed between end transducer elements in the series; each element in the plurality of inductively coupled elements is electrically connected to an adjacent element; and the second connection is configured as a changeable connection that is configured to couple to fixed taps or to slide continuously the elements or a combination thereof.